C2.2 Neural signaling

Question 1

Propagation of nerve impulse

Answer 1

Action potential in one part of the axon triggers an action potential in the next part

Question 2

1. Depolarization (opening of voltage gated Na+ channels) - process

Answer 2

Na+ channels open if resting potential rises to the threshold potential of -50mV - triggers the opening of more Na+ channels (positive feedback loop) until influx of NA+ reaches +30mV

Question 3

2. Repolarization (opening of voltage gated K+ channels) - process

Answer 3

Na+ channels close, triggers opening of K+ channels; causing K+ to diffuse out of neuron until -70mV reached

Question 4

Summation

Answer 4

The accumulative effect of multiple releases of neurotransmitters to trigger an action potential

Question 5

Resting potential of a Neuron

Answer 5

-70mv

Question 6

Charge imbalance of Neuron

Answer 6

Inside of the Neuron relatively negative compared to the outside

Question 7

Saltatory conduction

Answer 7

The jumping/skipping motion of nerve impulses from one node of Ranvier to another - speeds up nerve propagation

Question 7

Nerve conduction velocity

Answer 7

1. Velocity increased by Myelination
2. Velocity increased by larger surface area
3. Velocity increased at warmer temperature

Question 8

Action potential

Answer 8

Rapid change in electrical charge across the neuron (inside and outside)

Question 9

Exogenous chemicals

Answer 9

Chemicals which come from outside of the body, and enter the body

Question 10

Neonicotinoid pesticides

Answer 10

Causes permanent binding of acetylcholine to Na+ ion channel receptors, causing irreversible flow of Na+ into muscles causing paralysis and death.

Question 11

Acetylcholine (muscles) - process

Answer 11

Binds to post-synaptic Na+ ion channel receptors, opening them. Acetylcholine is then rapidly broken down by enzyme acetylcholinesterase, closing the channel.

Question 12

Cocaine

Answer 12

Binds to dopamine receptors, blocking reuptake of dopamine, causing build up of dopamine in synaptic cleft & continuous excitement of post-synaptic neuron.

Question 13

Excitatory Neurotransmitters

Answer 13

Make membrane potentials less negative (depolarize)

Question 14

Inhibitory Neurotransmitters

Answer 14

Make membrane potentials more negative (repolarize)

Question 15

“All or nothing” Principle

Answer 15

Unless the threshold potential is reached there is no action potential

Question 16

Resting potential

Answer 16

Imbalance across neuron membrane, due to unequal number of ions - when 3 Na+ ions are pumped out, only 2 K+ ions are pumped in.